my car has a cel on but when the vtec crossover occurs it instantly turns off. as the rpms fall below the crossover point it turns right back on. i have tried to check the codes. when i jump the 2 wire connector under the dash the cel just stays on. it never flashes any codes no matter what i do. i have reset the ecu by unplugging the fuse under the hood and still the same thing. it seems like there may be a grounding issue or something but i dont know??? any ideas on where to look?

it turned out to not be in the ecu, as it was doing the same thing with a stock p28. however, it did eventually start throwing a code 22 (vtec pressure switch). found that the plug on it was broken and didnt plug tightly. messed with it, reset the ecu and i have no more codes and no more weird cel. i still cant explain exactly why the cel was turning off when i went into vtec, but i guess it was just a bad connection all along.